Answer: a.Marcus Aurelius
Explanation:
The Equestrian statue of Marcus Aurelius was considered so important that many replicas of it have been made.
The message it conveyed is one of peace and because it was incorrectly thought to be a statue of CONSTANTINE THE GREAT who was a Christian emperor, the Christians did not destroy it like they did many others thought to inspire pagan worship making it a bit of a rare breed.
There are replicas at Brown University, Warsaw and Campidoglio with the original based in Rome.